In can interior coating systems, various spray heads and, respectively, spray arms are utilized for coating purposes, namely for the application of powder varnishes as well as wet varnishes. More generally, the working station at the arm projecting into the interior of the can must be exchanged relatively frequently in can interior treatment systems, such as, for example, in systems for melting applied powder on the interior of the can.
Although in can interior coating systems used at present the spray arms can be interchanged, the exchanging procedure takes a relatively long period of time since all feed and discharge lines for the coating medium, for air, for current, etc., must be individually disconnected and, respectively, reattached before the new spray arm section can be placed on the arm of the coating system and there locked into place.
Therefore, it is an object of the present invention to provide a device making it possible to effect quick interchanging of such a section in a can interior treatment system.
According to the invention, this is attained with a device for the interchangeable connection at a section of an internal can treatment arm to this arm wherein the device comprises a quick-action coupling.
A device of this invention comprises preferably respectively one planar or curved contact surface at the section, such as, for example, at the spray arm, and at the arm of the system to which the section is connected, as well as at least one locking member pressing the contact surfaces together.
In order to attach the interchangeable section, such as, for example, the spray arm, in the correct position to the arm of the can interior treatment system, there are furthermore provided positioning members preferably at the contact surfaces, these members permitting the locking action of the locking member to take place only in a predetermined relative position of the two surfaces.
It is important in connecting the section, such as the spray arm, to the arm of the can interior treatment system to also establish the connection of the feed and discharge conduits, such as, for example, for the coating medium, for the current, for measuring instrument connections, and so forth. This is accomplished by operationally safe attachment of the connections between the arm and the section by the locking action with the aid of the locking member. This is done, for example, by providing that the conduits either are in sealing contact during the positionally correct joining of the contact surface, or exhibit plug connections which are plugged together during the joining of the contact surfaces.
It may happen during the rapid interchanging of the section that the contact surfaces are contaminated so that tight pressure contact between the two contact surfaces is made difficult. For this reason, and for establishing a flexible locking action, it is furthermore proposed to arrange at least one sealing ring, for example at the periphery of one of the contact surfaces in order to sealingly join the surfaces in the separating plane by the locking action. In this case, the contact surfaces need not be in direct contact in the pressed-together condition.
In order to press the contact surfaces against each other, it is suggested for the sake of simplification to utilize a sleeve nut as the locking member. Preferably, this sleeve nut is designed in such a way that even a rotation by a relatively small angle already ensures the locking action.
In a further version of an embodiment, it is suggested to utilize a bayonet catch, the locking member forming part thereof.
In another version of the embodiment, it is proposed to fashion the locking member as a non-slip plug. In this arrangement, the length of the plug or, respectively, the corresponding socket must be designed so that, in the plugged-in condition, any deflection of the section relatively to the arm is impossible. Preferably, in this connection, either the surface of the plug or the inside of the socket is fashioned with a material having high surface friction, thus producing a maximally high frictional resistance between the socket and the plug. The material involved can be, for example, a synthetic resin or elastomeric materials. Pulling apart of socket and plug is possible only by exertion of an external force.
The device according to this invention is suited, in particular, for the attachment of a can seam coating head as a section to an arm of a can interior coating system.
The device according to the invention will be described hereinbelow by way of example with reference to the accompanying figures.